1 # [Google Closure Compiler](https://developers.google.com/closure/compiler/)
3 The [Closure Compiler](https://developers.google.com/closure/compiler/) is a tool for making JavaScript download and run faster. It is a true compiler for JavaScript. Instead of compiling from a source language to machine code, it compiles from JavaScript to better JavaScript. It parses your JavaScript, analyzes it, removes dead code and rewrites and minimizes what's left. It also checks syntax, variable references, and types, and warns about common JavaScript pitfalls.
6 * [Download the latest version](http://dl.google.com/closure-compiler/compiler-latest.zip)
7 * See the [Google Developers Site](https://developers.google.com/closure/compiler/docs/gettingstarted_app) for documentation including instructions for running the compiler from the command line.
9 ## Options for Getting Help
10 1. Post in the [Closure Compiler Discuss Group] (https://groups.google.com/forum/#!forum/closure-compiler-discuss)
11 2. Ask a question on [Stack Overflow](http://stackoverflow.com/questions/tagged/google-closure-compiler)
12 3. Consult the [FAQ](https://github.com/google/closure-compiler/wiki/FAQ)
14 ## Building it Yourself
16 Note: The Closure Compiler requires [Java 7 or higher](http://www.java.com/).
18 ### Using [Ant](http://ant.apache.org/)
20 1. Download the [Ant build tool](http://ant.apache.org/bindownload.cgi).
22 2. At the root of the source tree, there is an Ant file named ```build.xml```.
23 To use it, navigate to the same directory and type the command
29 This will produce a jar file called ```build/compiler.jar```.
31 ### Using [Eclipse](http://www.eclipse.org/)
33 1. Download and open the [Eclipse IDE](http://www.eclipse.org/).
34 2. Navigate to ```File > New > Project ...``` and create a Java Projet. Give
36 3. Select ```Create project from existing source``` and choose the root of the
37 checked-out source tree as the existing directory.
38 3. Navigate to the ```build.xml``` file. You will see all the build rules in
39 the Outline pane. Run the ```jar``` rule to build the compiler in
40 ```build/compiler.jar```.
44 On the command line, type
47 java -jar compiler.jar
50 This starts the compiler in interactive mode. Type
56 then hit "Enter", then hit "Ctrl-Z" (on Windows) or "Ctrl-D" (on Mac or Linux)
57 and "Enter" again. The Compiler will respond:
63 The Closure Compiler has many options for reading input from a file, writing
64 output to a file, checking your code, and running optimizations. To learn more,
68 java -jar compiler.jar --help
71 More detailed information about running the Closure Compiler is available in the
72 [documentation](http://code.google.com/closure/compiler/docs/gettingstarted_app.html).
74 ## Compiling Multiple Scripts
76 If you have multiple scripts, you should compile them all together with one
80 java -jar compiler.jar --js_output_file=out.js in1.js in2.js in3.js ...
83 You can also use minimatch-style globs.
86 # Recursively include all js files in subdirs
87 java -jar compiler.jar --js_output_file=out.js 'src/**.js'
89 # Recursively include all js files in subdirs, exclusing test files.
90 # Use single-quotes, so that bash doesn't try to expand the '!'
91 java -jar compiler.jar --js_output_file=out.js 'src/**.js' '!**_test.js'
94 The Closure Compiler will concatenate the files in the order they're passed at
97 If you're using globs or many files, you may start to run into
98 problems with managing dependencies between scripts. In this case, you should
99 use the [Closure Library](https://developers.google.com/closure/library/). It
100 contains functions for enforcing dependencies between scripts, and Closure Compiler
101 will re-order the inputs automatically.
105 1. First make sure that it is really a bug and not simply the way that Closure Compiler works (especially true for ADVANCED_OPTIMIZATIONS).
106 * Check the [official documentation](https://developers.google.com/closure/compiler/)
107 * Consult the [FAQ](https://github.com/google/closure-compiler/wiki/FAQ)
108 * Search on [Stack Overflow](http://stackoverflow.com/questions/tagged/google-closure-compiler) and in the [Closure Compiler Discuss Group](https://groups.google.com/forum/#!forum/closure-compiler-discuss)
109 2. If you still think you have found a bug, make sure someone hasn't already reported it. See the list of [known issues](https://github.com/google/closure-compiler/issues).
110 3. If it hasn't been reported yet, post a new issue. Make sure to add enough detail so that the bug can be recreated. The smaller the reproduction code, the better.
112 ### Suggesting a Feature
113 1. Consult the [FAQ](https://github.com/google/closure-compiler/wiki/FAQ) to make sure that the behaviour you would like isn't specifically excluded (such as string inlining).
114 2. Make sure someone hasn't requested the same thing. See the list of [known issues](https://github.com/google/closure-compiler/issues).
115 3. Read up on [what type of feature requests are accepted](https://github.com/google/closure-compiler/wiki/FAQ#how-do-i-submit-a-feature-request-for-a-new-type-of-optimization).
116 4. Submit your reqest as an issue.
118 ### Submitting patches
119 1. All contributors must sign a contributor license agreement. See the [CONTRIBUTORS](https://raw.githubusercontent.com/google/closure-compiler/master/CONTRIBUTORS) file for details.
120 2. To make sure your changes are of the type that will be accepted, ask about your patch on the [Closure Compiler Discuss Group](https://groups.google.com/forum/#!forum/closure-compiler-discuss)
121 3. Fork the repository.
122 4. Make your changes.
123 5. Submit a pull request for your changes. A project developer will review your work and then merge your request into the project.
125 ## Closure Compiler License
127 Copyright 2009 The Closure Compiler Authors.
129 Licensed under the Apache License, Version 2.0 (the "License");
130 you may not use this file except in compliance with the License.
131 You may obtain a copy of the License at http://www.apache.org/licenses/LICENSE-2.0.
133 Unless required by applicable law or agreed to in writing, software
134 distributed under the License is distributed on an "AS IS" BASIS,
135 WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
136 See the License for the specific language governing permissions and
137 limitations under the License.
139 ## Dependency Licenses
143 Two copies of Rhino exist in this repository:
148 <td><code>lib/rhino</code></td>
153 <td>http://www.mozilla.org/rhino</td>
163 <td>Netscape Public License and MPL / GPL dual license</td>
168 <td>Mozilla Rhino is an implementation of JavaScript for the JVM.</td>
172 <td>Local Modifications</td>
173 <td>Minor changes to parsing JSDoc that usually get pushed
174 up-stream to Rhino trunk.</td>
182 <code>src/com/google/javascript/rhino</code>, <code>test/com/google/javascript/rhino</code>
188 <td>http://www.mozilla.org/rhino</td>
193 <td>1.5R3, with heavy modifications</td>
198 <td>Netscape Public License and MPL / GPL dual license</td>
203 <td>A partial copy of Mozilla Rhino. Mozilla Rhino is an
204 implementation of JavaScript for the JVM. The JavaScript parser and
205 the parse tree data structures were extracted and modified
206 significantly for use by Google's JavaScript compiler.</td>
210 <td>Local Modifications</td>
211 <td>The packages have been renamespaced. All code not
212 relevant to parsing has been removed. A JsDoc parser and static typing
213 system have been added.</td>
222 <td><code>lib/args4j.jar</code></td>
227 <td>https://args4j.dev.java.net/</td>
242 <td>args4j is a small Java class library that makes it easy to parse command line
243 options/arguments in your CUI application.</td>
247 <td>Local Modifications</td>
257 <td><code>lib/guava.jar</code></td>
262 <td>http://code.google.com/p/guava-libraries/</td>
272 <td>Apache License 2.0</td>
277 <td>Google's core Java libraries.</td>
281 <td>Local Modifications</td>
291 <td><code>lib/jsr305.jar</code></td>
296 <td>http://code.google.com/p/jsr-305/</td>
301 <td>svn revision 47</td>
311 <td>Annotations for software defect detection.</td>
315 <td>Local Modifications</td>
325 <td><code>lib/jarjar.jar</code></td>
330 <td>http://jarjar.googlecode.com/</td>
340 <td>Apache License 2.0</td>
345 <td>A utility for repackaging Java libraries.</td>
349 <td>Local Modifications</td>
359 <td><code>lib/junit.jar</code></td>
364 <td>http://sourceforge.net/projects/junit/</td>
374 <td>Common Public License 1.0</td>
379 <td>A framework for writing and running automated tests in Java.</td>
383 <td>Local Modifications</td>
393 <td><code>lib/protobuf-java.jar</code></td>
398 <td>http://code.google.com/p/protobuf/</td>
408 <td>New BSD License</td>
413 <td>Supporting libraries for protocol buffers,
414 an encoding of structured data.</td>
418 <td>Local Modifications</td>
429 <code>lib/ant.jar</code>, <code>lib/ant-launcher.jar</code>
435 <td>http://ant.apache.org/bindownload.cgi</td>
445 <td>Apache License 2.0</td>
450 <td>Ant is a Java based build tool. In theory it is kind of like "make"
451 without make's wrinkles and with the full portability of pure java code.</td>
455 <td>Local Modifications</td>
465 <td><code>lib/json.jar</code></td>
470 <td>http://json.org/java/index.html</td>
475 <td>JSON version 20090211</td>
485 <td>JSON is a set of java files for use in transmitting data in JSON format.</td>
489 <td>Local Modifications</td>
499 <td><code>lib/mockito-core.jar</code></td>
504 <td>https://code.google.com/p/mockito</td>
519 <td>Mockito is an open source testing framework for Java. The framework allows the
520 creation of Test Double objects (called "Mock Objects") in automated unit tests
521 for the purpose of Test-driven Development (TDD) or Behavior Driven Development
526 <td>Local Modifications</td>
536 <td><code>lib/objenesis.jar</code></td>
541 <td>http://objenesis.org</td>
551 <td>Apache 2.0 license</td>
556 <td>Depended by lib/mockito-core.jar, not used directly.</td>
560 <td>Local Modifications</td>